Although the definitions are still valid, we do this much differently in the Marines. Our WOs and CWOs come from the enlisted side, not sure of the minimum grade, but normally Staff Sergeants and Gunnery Sergeants, and our LDOs come from our CWOs. The minimum rank for a Marine LDO is Captain. It's quite normal to see one of your CWO3s become a Captain and move on to a higher level billet. We also have CWOs serving as high as MARFOR staffs, so it's not all specialization.
It's always amazed me to meet LDO Ensigns and JGs on the boat. Most of them would tell me that they used to be Senior Chiefs or Master Chiefs.
I cannot imagine a single Master Sergeant/First Sergeant or Master Gunnery Sergeant/Sergeant Major becoming a 2ndLt under anything but the most dire circumstances (battlefeild promotion type stuff). The most senior enlisted turned officer (2ndLt) I ever met was a Gunny. It seems like most Marines wouldn't trade the prestige of the senior enlisted billets for the relative obscurity of being a Lieutenant.
Not good or bad here, it's just totally different.